Final answer:
To simplify the expression cos(π/2 * x), we use the co-function relationships between sine and cosine, which leads to the simplification as sin(x).
Step-by-step explanation:
The expression cos(π/2 * x) can be simplified using the trigonometric identities for sine and cosine functions. Particularly, we utilize the fact that sine and cosine functions are co-functions of each other, meaning sin(θ) = cos(π/2 - θ) and cos(θ) = sin(π/2 - θ). Therefore, cos(π/2 * x) = sin(π/2 - π/2 * x). Simplifying this we get cos(π/2 * x) = sin(x), because π/2 - π/2 * x equals x when x is factored out.